1. Field of the Invention
The present invention relates to a heat sink assembly, and particularly to a heat sink assembly retainer device for fixing a heat sink on a chip unit mounted on a printed circuit board
2. Description of Related Art
Heat produced by an electric chip unit during operation needs to be timely dissipated to ensure proper operation of the chip unit. To achieve this, a heat sink assembly is generally used. U.S. Pat. No. 5,671,118 discloses a socket forming two opposite claws, a chip unit mounted on the socket, a heat sink posited on the chip unit, and a two piece clip having two end positions respectively engaging with the claws and a spring section pressing the heat sink against the chip unit. The clip ensures good thermal connection between the chip unit and the heat sink, promoting conduction of the heat generated by the chip unit away via the heat sink.
However, the connection between the prior art clip and the socket is not secure, thus, when subjected to vibration or shock, the clip may separate from the socket, which will cause the heat sink to lose intimate engagement with the chip unit, decreasing dissipation rate of the heat generated by the chip unit.
Hence, an improved heat sink assembly retainer device is required to overcome the disadvantages of the conventional heat sink assembly retainer.
Accordingly, an object of the present invention is to provide a heat sink assembly retainer device securely fixing a heat sink on a chip so that an intimate engagement between the chip and the heat sink can always be ensured even when the heat sink assembly is subjected to vibration a shook.
In order to achieve the object set forth, a heat sink assembly retainer device for fixing a heat sink on an electronic integrated chip is provided. The heat sink includes a horizontal base and a plurality of cooling fins. The base defines a receiving channel between the cooling fins. A pair of securing flanges extends outwardly beside the cooling fins. The retainer device includes a mounting frame, a base plate and a mounting lever. The mounting frame includes a pair of opposite retaining plates and a pair of spring plates connecting the retaining plates. The retaining plates and the spring plates define a receiving space for receiving the heat sink. Each of the retaining plates defines a clip in the middle thereof for engaging with a lower edge of the heat sink, and a pair of latches on lateral ends thereof. The base plate forms four receiving projections extending upwardly which define notches for receiving the latches thereby mounting the mounting frame on the base plate. The mounting lever has a base pole received in the receiving channel. The base pole defines protrusions on opposite sides for pressing against the spring plates and the securing flanges.